/////////////////////////////////////////////////////////////////////////////
// Name:        md5.cpp
// Purpose:     MD5 file checksum
// Author:      Francesco Montorsi
// Created:     2005/07/13
// RCS-ID:      $Id: md5.cpp,v 1.5 2005/10/20 16:06:01 frm Exp $
// Copyright:   (c) 2005 Francesco Montorsi
// Licence:     wxWidgets licence + RDS Data Security license
/////////////////////////////////////////////////////////////////////////////

/*
 **********************************************************************
 ** Copyright (C) 1990, RSA Data Security, Inc. All rights reserved. **
 **                                                                  **
 ** License to copy and use this software is granted provided that   **
 ** it is identified as the "RSA Data Security, Inc. MD5 Message     **
 ** Digest Algorithm" in all material mentioning or referencing this **
 ** software or this function.                                       **
 **                                                                  **
 ** License is also granted to make and use derivative works         **
 ** provided that such works are identified as "derived from the RSA **
 ** Data Security, Inc. MD5 Message Digest Algorithm" in all         **
 ** material mentioning or referencing the derived work.             **
 **                                                                  **
 ** RSA Data Security, Inc. makes no representations concerning      **
 ** either the merchantability of this software or the suitability   **
 ** of this software for any particular purpose.  It is provided "as **
 ** is" without express or implied warranty of any kind.             **
 **                                                                  **
 ** These notices must be retained in any copies of any part of this **
 ** documentation and/or software.                                   **
 **********************************************************************
 */



// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
#pragma hdrstop
#endif

// includes
#include "md5.h"

// C headers for MD5
#include <sys/types.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>




// ----------------
// MD5 by RSA
// ----------------
	
char * MD5End(MD5_CTX *ctx, char *buf)
{
    int i;
    unsigned char digest[MD5_HASHBYTES];
    char hex[]="0123456789abcdef";

    if (!buf)
    {
     	buf = (char *)malloc(33);
    }
    
    if (!buf)
        return 0;
    
    MD5Final(digest,ctx);
    for (i=0;i<MD5_HASHBYTES;i++) {
        buf[i+i] = hex[digest[i] >> 4];
        buf[i+i+1] = hex[digest[i] & 0x0f];
    }
    buf[i+i] = '\0';
    return buf;
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
void MD5Final(unsigned char digest[16], MD5_CTX *ctx)
{
    unsigned count;
    unsigned char *p;

    /* Compute number of bytes mod 64 */
    count = (ctx->bits[0] >> 3) & 0x3F; 

    /* Set the first char of padding to 0x80.  This is safe since there is
       always at least one byte free */
    p = ctx->in + count;
    *p++ = 0x80;

    /* Bytes of padding needed to make 64 bytes */
    count = 64 - 1 - count;

    /* Pad out to 56 mod 64 */
    if (count < 8) {
        /* Two lots of padding:  Pad the first block to 64 bytes */
        memset(p, 0, count);
        //[TCC] byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (unsigned int *) ctx->in);

        /* Now fill the next block with 56 bytes */
        memset(ctx->in, 0, 56);
    } else {
        /* Pad block to 56 bytes */
        memset(p, 0, count - 8);   
    }
    //[TCC] byteReverse(ctx->in, 14);

    /* Append length in bits and transform */
    ((unsigned int *) ctx->in)[14] = ctx->bits[0];
    ((unsigned int *) ctx->in)[15] = ctx->bits[1];

    MD5Transform(ctx->buf, (unsigned int *) ctx->in);
    //[TCC] byteReverse((unsigned char *) ctx->buf, 4);   
    memcpy(digest, ctx->buf, 16);
    memset((char *) ctx, 0, sizeof(ctx));       /* In case it's sensitive */
}

void MD5Init(MD5_CTX *ctx)
{
    ctx->buf[0] = 0x67452301;
    ctx->buf[1] = 0xefcdab89;
    ctx->buf[2] = 0x98badcfe;
    ctx->buf[3] = 0x10325476;

    ctx->bits[0] = 0;
    ctx->bits[1] = 0;
}

void MD5Update(MD5_CTX *ctx, unsigned char const *buf, unsigned len)
{
    unsigned int t;

    /* Update bitcount */

    t = ctx->bits[0];
    if ((ctx->bits[0] = t + ((unsigned int) len << 3)) < t)
        ctx->bits[1]++;         /* Carry from low to high */
    ctx->bits[1] += len >> 29;

    t = (t >> 3) & 0x3f;        /* Bytes already in shsInfo->data */

    /* Handle any leading odd-sized chunks */

    if (t) {
        unsigned char *p = (unsigned char *) ctx->in + t;

        t = 64 - t;
        if (len < t) {
            memcpy(p, buf, len);
            return;
        }
        memcpy(p, buf, t);
        //[TCC] byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (unsigned int *) ctx->in);
        buf += t;
        len -= t;
    }
    /* Process data in 64-byte chunks */

    while (len >= 64) {
        memcpy(ctx->in, buf, 64);
        //[TCC] byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (unsigned int *) ctx->in);
        buf += 64;
        len -= 64;
    }

    /* Handle any remaining bytes of data. */

    memcpy(ctx->in, buf, len);
}


/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))   
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
        ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
void MD5Transform(unsigned int buf[4], unsigned int const in[16])
{
    register unsigned int a, b, c, d;

    a = buf[0];
    b = buf[1];
    c = buf[2];
    d = buf[3];

    MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7); 
    MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
    MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
    MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
    MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7); 
    MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
    MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
    MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22); 
    MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);  
    MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12); 
    MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
    MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
    MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7); 
    MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
    MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
    MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

    MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);  
    MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);  
    MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
    MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20); 
    MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);  
    MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9); 
    MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
    MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20); 
    MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);  
    MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9); 
    MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14); 
    MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20); 
    MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
    MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);  
    MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
    MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

    MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
    MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
    MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
    MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
    MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);  
    MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11); 
    MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16); 
    MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
    MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4); 
    MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11); 
    MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16); 
    MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23); 
    MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);  
    MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
    MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
    MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23); 

    MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
    MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
    MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
    MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21); 
    MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6); 
    MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10); 
    MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
    MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21); 
    MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);  
    MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
    MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15); 
    MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
    MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);  
    MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
    MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15); 
    MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21); 

    buf[0] += a;
    buf[1] += b;
    buf[2] += c;
    buf[3] += d;
}
 

#ifndef REVERSEBYTE
#define byteReverse(buf, len)   /* Nothing */
#else
void byteReverse(unsigned char *buf, unsigned longs);

/*
 * Note: this code is harmless on little-endian machines.
 */
void byteReverse(unsigned char *buf, unsigned longs)
{
    unsigned int t;
    do {
        t = (unsigned int) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
            ((unsigned) buf[1] << 8 | buf[0]);
        *(unsigned int *) buf = t;  
        buf += 4;
    } while (--longs);
}
#endif



// --------------------------
// wxMD5 - static functions
// --------------------------

wxString wxMD5::GetMD5(const wxString &string)
{
	int length = (int)string.Len();
	//wxStringBuffer buf(string, lenght);

	MD5_CTX ctx;
	char tmp[40];		// MD5 are fixed sized to 32 chars
	
	MD5Init(&ctx);
	MD5Update(&ctx, (const unsigned char*)string.GetData(), length*sizeof(wxChar));
	MD5End(&ctx, tmp);

	return wxString(tmp, wxConvUTF8);
}

wxString wxMD5::GetFileMD5(wxInputStream &stream)
{
    unsigned char buffer[102400];
	char tmp[40];		// MD5 are fixed sized to 32 chars
    MD5_CTX ctx;

	if (!stream.IsOk())
		return wxEmptyString;

   	MD5Init(&ctx);

    do
    {
		if (stream.Read(buffer, sizeof(buffer)).LastRead() <= 0)
			return wxEmptyString;

    	MD5Update(&ctx, buffer, (unsigned int)stream.LastRead());
    } while (!stream.Eof());

	MD5End(&ctx, tmp);
    return wxString(tmp, wxConvUTF8);
}

wxString wxMD5::GetFileMD5(const wxString &filename)
{ 
	wxFileInputStream stream(filename); 
	return GetFileMD5(stream); 
}
